This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
The issue of power consumption in handheld devices such as mobile telephones has become increasingly problematic in recent years and is expected to continue to be an issue in the future. In particular, increased power consumption in such terminals increases terminal temperature. In many devices, however, the internal temperature has already reached its uppermost limit. Additionally, increased power consumption shortens the terminal's usage time unless the terminal's battery capacity is not correspondingly increased. However, terminals have been becoming both smaller and thinner in recent years, and this trend will likely continue. This trend has led to the unfortunate situation where terminal batteries need to be smaller at the same time that power consumption is increasing.
In response to the above constraints, a number of different mechanisms have been developed for broadcast and multicast systems with the goal of decreasing the power consumption of broadcast/multicast receivers. In radio communication systems, the radio spectrum is a scarce resource and therefore should be used in the most efficient manner possible.
In broadcasting systems, the data rate of an input stream coming to a device is not precisely known at a given moment. Instead, only the statistical behavior of the input stream is known. This can result in a capacity allocation problem, when several input streams having unknown characteristics (e.g., unknown bitrates) are multiplexed into one signal that will be transmitted over a broadcast/multicast system. A number of systems have been implemented to address the above. The issue of power consumption has been conventionally addressed in part, for example, through the use of different time division multiplexing (TDM) systems. In these systems, either the transmitter, the receiver, or both devices may power off portions thereof according to the particular TDM arrangement being used. Another option for addressing the power consumption issue has been to use frequency division. In frequency division arrangements, a used frequency band is divided into smaller sub-bands, and the transmitter or receiver uses only one or more of these sub-bands, thereby leading to smaller power consumption.